Organosilicon compounds that contain amino groups and alkoxysilyl groups are used as silane coupling agents. For example, alkoxysilanes that contain primary amino groups and expressed by the formulae H2NC3H6Si(OC2H5)3 and H2NC2H4NHC3H6Si(OCH3)3 are known. However, a disadvantage of such compounds is that when compounds that contain primary amino groups are used in conjunction with organic resins, such as epoxy resins that utilize amines as curing catalysts, the amino-group containing compounds exert an adverse effect on the curability of the resins. Therefore, it has been proposed to use alkoxysilanes of the formulae shown as disclosed in U.S. Pat. No. 5,476,884 and JP 2002-193976 A, with secondary amino groups such as PhNHC3H6Si(OCH3)3 where Ph is a phenyl group,    CH3(CH2)3NHC3H6Si(OCH3)3, or alkoxysilanes with tertiary amino groups such as (C4H9)2NC3H6Si(OCH3)3.
Although the alkoxysilanes with such secondary or tertiary amino groups reduce the effect on curability of the resins to some extent, their adhesion-improving effect with respect to various substrates is insignificant, and their silane coupling function is insufficient. Another disadvantage of the last mentioned compounds is that, in the manufacturing process, they produce a large amount of by-products in the form of amine hydrochloric salts.
On the other hand, organosilicon compounds with amide groups are known in the art including alkoxysilanes such as    H2NCONHC3H6Si(OC2H5)3 and H2NCOC3H6Si(OC2H5)3 as in U.S. Pat. No. 3,033,815 (May 8, 1962). Furthermore, U.S. Pat. No. 4,209,455 (Jun. 24, 1980) discloses alkoxysilanes which contain secondary amide groups such as H2NC2H4NHCOC3H6Si(OC2H5)3 and    C18H37NHCOC2H4NHC3H6Si(OC2H5)3.
However, even these alkoxysilanes still exert unfavorable effect on curability and adhesion-imparting properties of the resins, and therefore are not yet sufficient in their function as silane coupling agents.